Nethery was born in Lewisville, Arkansas to Daniel Thompson "Tom" Nethery (1890–1966) and his wife, the former Ruby Estelle Byrd (1892–1982). She was married to Clu Gulager--who played Billy the Kid on the NBC television series, The Tall Man-- from 1960 to 2003. Their sons are Tom and John Gulager. Nethery died in Los Angeles on January 6, 2003, at age 73.